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Crystal Lab › Prototype structures › Trigonal

β-CuI (Kurdyumova)

Trigonal · space group P3m1 (No. 156) · Pearson hP12

Symmetry elements and Wyckoff positions (interactive)

β-CuI (Kurdyumova) in P3m1

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit cell

Lattice constants
a = 4.250 Å, b = 4.250 Å, c = 20.860 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
326.3 ų
Atoms in the conventional cell
12 (Cu 6, I 6)
Formula units Z
6
Pearson symbol
hP12 — hexagonal / trigonal, primitive lattice, 12 atoms per conventional cell
Symmetry operations
6 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cu4Cu1a10.00001.00000.4583
Cu5Cu1a10.00001.00000.7917
Cu6Cu1a10.00001.00000.1250
I10I1a10.00001.00000.3333
I11I1a10.00001.00000.6667
I12I1a10.00001.00000.0000
Cu1Cu1b10.33330.66670.3750
Cu2Cu1b10.33330.66670.7083
I7I1b10.33330.66670.5000
I8I1b10.33330.66670.8333
Cu3Cu1c10.66670.33330.0417
I9I1c10.66670.33330.1667

The multiplicity and the Wyckoff letter say how many copies of the site the group makes in one cell and on which kind of symmetry element the site sits; the 12 atoms drawn above are these sites multiplied by all 6 operations. Press Wyckoff under Colour to see the sites, and tick a symmetry element on the left to see which atoms lie on it.

How to read the label

AB_hP12_156_3a2bc_3a2bc-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP12, then the space-group number 156, then the Wyckoff letters occupied by each element in turn (Cu: 1a; Cu: 1a; Cu: 1a; I: 1a; I: 1a; I: 1a; Cu: 1b; Cu: 1b; I: 1b; I: 1b; Cu: 1c; I: 1c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: \beta-CuI (Kurdyumova).

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hP12_156_3a2bc_3a2bc-001 (M. J. Mehl et al., Comput. Mater. Sci. 136, S1 (2017); D. Hicks et al., ibid. 161, S1 (2019) and 199, 110450 (2021); S. Eckert et al., ibid. 240, 112988 (2024)). Symmetry elements, Wyckoff assignment and the diagram are computed on this page from the group operations.

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